In many instances, it is difficult if not impossible to administer medication in capsule form to patients. This is particularly true for patients who may be comatose or otherwise physically unable to swallow the pills. For those people, in the prior art, the pills were ground with a mortar and pestle. The powder was transferred to a liquid-filled container and mixed with the liquid. The suspension was then either swallowed, or a syringe was filled with the suspension and injected into an intravenous tube or other tube generally used in hospital settings.
The prior art technique carried several drawbacks. The most serious of these were the risks of low and unpredictable compliance and cross-contamination. As the pill was crushed in a mortar and then transferred to another container before being administered, a nurse using extreme care could not help but lose some of the pill as residue on the mortar, pestle, etc. Furthermore, this residue would necessarily vary both in quantity and content from dose to dose to thereby perhaps alter the dosage administered from that intended. In extreme situations, this could interfere with achieving the desired medical result.
The undesired, but inescapable, residue also created an unavoidable risk of cross-contamination as the same mortar and pestle were typically re-used for the same and other patients; as well.
Moreover, the prior art technique was very time consuming as the nurse needed to use care and caution to avoid spillage, which translated into increased nurse or medical technician time and expense.
Other pill crushing devices are also known in the prior art. However, similar to the mortar and pestle technique discussed above, these devices were designed to grind or crush the pill in one compartment, transfer the powder to another liquid-filled container where the powder was dissolved or suspended and then administered. These devices similarly carried the risks of contamination, cross-contamination, spillage and waste, and were again time consuming.
The invention disclosed in the parent hereto, as cross-referenced above, overcomes the foregoing problems by providing a pill crushing syringe which is adapted to crush medication, preferably a pill, and mix the resulting powder with liquid all within the syringe itself, and then administer the suspension with the same syringe. Generally the syringe disclosed in the parent includes a barrel and a plunger. The syringe has two opposing abraded surfaces, one on the plunger and one in the barrel bottom, to crush a pill placed in the barrel by the plunger as it is advanced to the bottom of the barrel. The pill could even be "ground" by rotating the plunger within the barrel to achieve a complete breakdown of the pill into small and regularly sized particles. In an alternate embodiment of the invention disclosed in the parent, the bottom of the barrel may be threaded so that it may also be rotated, thereby permitting both abraded surfaces to be positively driven with respect to each other. The barrel includes an aperture and a catheter located at the bottom of the barrel for drawing liquid into the barrel to mix with the crushed pill particles. The plunger includes a sealing gland providing an airtight relationship between the plunger and the barrel to assist in drawing liquid into the barrel by withdrawing the plunger from the barrel when the catheter tip is submerged in the-liquid. The suspension of the liquid and crushed pill particles is administered by advancing the plunger into the barrel thereby forcing the suspension through the catheter and into a tube attached to the patient.
Generally, the method of the invention disclosed in the parent comprises providing a pill crushing syringe including a barrel and a plunger with opposing abraded surfaces so that medication, preferably a pill, placed in the barrel is crushed as the plunger is "bottomed" within the barrel, placing a pill into the barrel, crushing the pill, adding liquid to the barrel thereby suspending the powder in the liquid, and flushing the suspension.
The apparatus and method of the parent invention are significant improvements over the prior art in that pills are crushed, the resulting powder mixed with liquid, and the suspension administered all with the same syringe. Because the pill is crushed in a closed container and the powder need not be transferred for mixing with the liquid, the risk of cross-contamination and spillage is greatly reduced while consistency of compliance is achieved. Moreover, the abraded surfaces used to crush the pills are exposed to the liquid drawn into the barrel which provides a "washing" action on the very surfaces used to grind the pill. This helps to minimize residue.
In addition to reducing the risk of waste and contamination, insuring a high dosage compliance rate, and eliminating the problem of cleaning the pestle and mortar, the invention disclosed in the parent saves nurses time allowing more medicinal dosages to be administered within the same time frame in a reliable manner. Further, the syringe may be made of plastic and used only once, thereby eliminating the risk of cross-contamination.
As disclosed in the continuation-in-part application of the parent disclosed above, Ser. No. 08/264,628, filed Jun. 23, 1994, the inventors have improved their earlier pill crushing syringe by providing a bi-level barrel having an open end, a closed end and a cylindrical wall, and a mating bi-level plunger having a tip end. As in the parent, the syringe has two opposing abraded surfaces, one on the plunger tip end and one on the barrel closed end to thereby crush a pill placed in the barrel as the plunger is advanced and rotated within the barrel. The present invention further includes an aperture through the barrel wall in spaced relation to the closed barrel end such that a pocket is formed by the barrel wall and the closed end between the aperture and the closed end. A substantially straight catheter is connected around and extends from the aperture. By holding the syringe upright, the crushed pill ingredients remain in this pocket prior to aspiration, thereby assuring high dosage integrity by prohibiting medication from escaping through the catheter.
In the parent, the preferred location of the aperture is adjacent the barrel closed end, and a "crooked" catheter is preferred to assure no medication escapes prior to aspiration. The "crooked" catheter arrangement provides quite favorable results. However, the pocket between the aperture and the barrel closed end of the present invention attains equally favorable dosage integrity while allowing the use of a substantially straight catheter. The straight catheter design is better suited for present injection molding technology and thus is significantly less expensive to manufacture.
An alternative means for crushing the pill into a powder provides a bi-level barrel and a bi-level plunger, wherein the barrel further includes a side opening with a hollow side arm extending from the side opening. A reinforced barrel wall section having an interior abraded surface is positioned opposite the side opening. A side entry plunger having an abraded tip end is movable within the side arm and the side entry plunger is adapted to engage the reinforced wall abraded surface as the side entry plunger advances within the hollow arm and into the barrel. A pill placed between the reinforced wall abraded surface and the side entry plunger abraded tip end is crushed as the side entry plunger is advanced into and rotated within the barrel.
Another alternative embodiment provides a cylinder with two plungers having opposing abraded tip ends adapted to crush a pill placed therebetween by advancing the plungers within the cylinder and rotating the plungers in opposite directions. A catheter is connected around and extends from an aperture through the cylinder wall. A space between the two plungers, which encompasses the crushed pill ingredients, may be positioned to be in fluid connection with the aperture thereby allowing aspiration of the pill ingredients.
Building on the invention disclosed above, the inventors herein have improved their earlier designs by providing a pill crushing syringe which is more economical to manufacture, has very favorable pill crushing and dosage compliance characteristics, and minimizes fluid residue within the syringe. Moreover, the syringe of the present invention is in closer visual conformity with typical syringes used in the health care field which minimizes operator apprehension commonly experienced when first using a new product. As in the parent, the syringe includes a barrel having a first open end, a generally closed second end, and a cylindrical wall therebetween as well as a plunger movable within the barrel. The syringe has two coaxially aligned opposing abraded surfaces, one on a tip end of the plunger and one on the second barrel end to thereby crush a pill placed in the barrel as the plunger is advanced and rotated within the barrel.
The present invention further includes an aperture near the center of the second barrel end and a substantially straight catheter extending from the aperture which visually resembles typical syringes. The plunger tip is conically shaped, the barrel second end is frustoconically shaped (because of the aperture through the center thereof), and each has an abraded surface of a protrusion pattern comprising a radially extending, alternating pattern of ridges and valleys. A plug extends from the center-of the plunger tip and is sized to prevent the opposing abraded surfaces from meshing which minimizes packing of the pill crushings within the valleys. By holding the syringe in its inverted vertical orientation while crushing the pill, the pill (and resulting pill particles) gravitate radially outwardly and downwardly along the conic plunger tip, principally following the valleys, and away from the aperture.
The radially extending protrusion pattern on the coaxially aligned opposing abraded surfaces provides a number of advantages over the pyramid-shaped protrusions arranged in a grid of intersecting lines and columns shown in the parent and continuation-in-part hereto. While the plug extending from the plunger tip prevents the opposing abraded surfaces from meshing, the ridges of the opposing abraded surfaces make contact and partially wipe each other when the plunger is rotated within the barrel. This partial wiping action helps remove any pill crushings which might otherwise be matted against the opposing ridges and creates a vibrating reciprocating action with the abraded surfaces as the plunger is rotated which facilitates a more complete crushing of the pill. The present invention reliably aligns the opposing ridges and valleys and reliably regulates the amount of wiping and the degree of vibrating reciprocation by assuring that two physical characteristics of the syringe are within tolerance: coaxial alignment of the abraded surfaces and the plug length.
There is no teaching of reliable alignment, or regulating the wiping and vibrating reciprocation with the prior art pill crushing abraded surfaces. Each prior art abraded surface typically contains 45 pyramids. Because the location, height, and width of 90 pyramids (45 on each abraded surface) must be individually accounted for, alignment is difficult to precisely control. Moreover, seating, the degree of vibrating reciprocation, and the precise portion of each pyramid which wipes opposing pyramids is difficult to measure and even more difficult to reliably repeat. Production of one or more of the pyramids out of tolerance (too fat, too tall, etc.) may significantly alter the pill crushing characteristics of those abraded surfaces. Perhaps more importantly, as the pyramid abraded surfaces are typically individually mounted to the pill crushing device after their separate manufacture, it is very difficult to maintain alignment of these separate surfaces. Thus, the radial protrusion pattern of the present invention provides functional advantages over the prior art in that alignment of opposing ridges and valleys and pill crushing characteristics are predictable and reliably repeatable by closely controlling only two of the syringe's physical dimensions (coaxial alignment of the abraded surfaces and the plug length) thereby enabling economic mass production of the pill crushing syringe.
When the pill is sufficiently crushed, the plunger is advanced fully into the barrel which forces the plug to block the catheter passage. With the catheter passage blocked, the syringe may be tilted downward and the catheter submerged in preparation for aspiration with minimal risk of the medication prematurely gravitating into the catheter. With this method, the pill crushings not only gravitate to the outer circumference of the plunger/barrel and away from the aperture when the syringe is vertically inverted, but the plug also physically blocks the aperture to prevent their escape. By preventing the opposing abraded surfaces from meshing, the plug also minimizes packing of the pill ingredients between the ridges and valleys allowing the pill particles to quickly and more completely dissolve during aspiration.
In the parent, the abraded surfaces are shown as orthogonal to the barrel and plunger axes and include a plurality of pyramid-shaped protrusions arranged in a grid of intersecting lines and columns. The location of the aperture in the parent is adjacent the barrel second end and a "crooked" catheter is utilized to assure no medication escapes prior to aspiration. The orthogonal, grid-like abraded surface pattern, and "crooked" catheter arrangement provide quite favorable results. However, centrally locating the catheter in the second barrel end (as opposed to the side) and utilizing a radial abraded surface pattern comprised of continuous ridges and valleys results in a design better suited for present injection molding technology and thus significantly less expensive to manufacture. Moreover, the radial protrusion pattern produces superb crushing results and, as explained above, the plug of the present invention assures a high degree of dosage integrity. The frustoconic shape of the barrel closed end minimizes any residual liquid within the syringe further contributing to the high-dosage compliance obtained by the present invention. Furthermore, because the present invention more closely resembles traditional syringes, health care personnel will be more receptive to the familiar style and less apprehensive when initially using the syringe.